I picked up a 1969 or 1970 full size blazer rear end 4 wheel drive 6 lug. I would like to find out the gear ratio it is. This is the number stamped on the axle housing tdf 0625w2.it will be going in my 52 truck thanks robert
The most accurate way to identify the ratio is to pull the cover and look at the ring gear stampings. If the housing has a tag, the gears could have been changed. From my experience the housing cast numbers don't reveal the ratio, instead they show the axle type: GM 10, Corp 14, Dana 44 ... http://coloradok5.com/axleguide.shtml
i can tell you right now it will most likely be either 3.08 or 3.73. you might get lucking and somebody swped in 4.10 or better but never count on it.
there might be a small metal tag on one of the diff cover bolts. you will probably just have to pull the cover off and drain the diff, the ### will be on the ring gear about 1/8" tall.